JP6340004B2 - Adhesive composition, adhesive sheet, and method for manufacturing semiconductor device - Google Patents

Description

  The present invention is particularly suitable for use in a step of die bonding a semiconductor element (semiconductor chip) to an organic substrate or a lead frame and a step of dicing a silicon wafer or the like and die bonding a semiconductor chip to an organic substrate or a lead frame. The present invention relates to an adhesive composition, an adhesive sheet having an adhesive layer made of the adhesive composition, and a method of manufacturing a semiconductor device using the adhesive sheet.

  A semiconductor wafer made of silicon, gallium arsenide or the like is manufactured in a large diameter state, and this wafer is cut and separated (diced) into element pieces (semiconductor chips) and then transferred to the next mounting step. At this time, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state where the semiconductor wafer is previously adhered to the adhesive sheet, and then transferred to the next bonding process.

  In order to simplify the processes of the pick-up process and the bonding process among these processes, various dicing / die-bonding adhesive sheets having both a wafer fixing function and a die bonding function have been proposed (Patent Document 1, etc.) ). The adhesive sheet disclosed in Patent Document 1 enables so-called direct die bonding, and the application step of the die bonding adhesive can be omitted.

  By the way, the required physical properties of recent semiconductor devices have become very strict. For example, in the connection of electronic components, a surface mounting method (reflow) is performed in which the entire package is exposed to a high temperature equal to or higher than the solder melting point. Furthermore, in recent years, the mounting temperature has increased to about 260 ° C. due to the shift to lead-free solder. For this reason, the stress generated inside the semiconductor package at the time of mounting becomes larger than before, and there is a high possibility of causing problems such as peeling at the adhesive interface and package cracks.

  Patent Document 1 discloses an acrylic polymer and epoxy having a weight average molecular weight (Mw) of 900,000 or more and a molecular weight distribution (Mw / Mn) of 7 or less, mainly for preventing adhesion between adhesive layers after dicing. An adhesive composition characterized by containing an epoxy resin and a thermosetting agent has been proposed.

Patent Document 1: Japanese Patent Application Laid-Open No. 2009-292888

  The present inventors paid attention to controlling the molecular weight distribution of the acrylic polymer from the viewpoint of the polymerization method as a means for solving the problem of achieving high package reliability. The adhesive composition of Patent Document 1 increases the weight average molecular weight Mw to relatively reduce the content of low molecular weight components, thereby preventing the plasticization of the adhesive due to the low molecular weight components. , Preventing adhesion between adhesive layers. However, since the molecular weight distribution of the acrylic polymer used in the adhesive disclosed in the examples of Patent Document 1 is relatively high, around 4, a weight average is necessary to sufficiently reduce the content of low molecular weight components. The molecular weight must be a large one of 1 million or more.

  Thus, when the weight average molecular weight of an acrylic polymer is high, there is a concern that it does not follow the recent unevenness of the chip surface, which is a cause of a decrease in adhesive strength. Further, since it is necessary to use an acrylic polymer having a high weight average molecular weight, the degree of freedom in designing the adhesive is narrowed.

  The present invention relates to an adhesive composition that can be bonded with sufficient adhesive strength, and in particular, can achieve high package reliability in a semiconductor device, an adhesive sheet having an adhesive layer made of the adhesive composition, and a semiconductor using the adhesive sheet It is an object of the present invention to provide a device manufacturing method.

  The present invention for solving the above problems includes the following gist.

(1) Acrylic polymer (A) having a weight average molecular weight (Mw) of 350,000 or more obtained by polymerizing an acrylic monomer by a living radical polymerization method using an organic tellurium-containing compound as a polymerization initiator, epoxy thermosetting Adhesive composition containing an adhesive resin (B) and a thermosetting agent (C).

(2) The adhesive composition according to (1), further comprising a crosslinking agent (D), wherein the acrylic polymer (A) has a functional group that reacts with the crosslinking agent.

(3) The adhesive composition according to (2), wherein the crosslinking agent (D) contains an isocyanate group and the acrylic polymer (A) contains a hydroxyl group.

(4) The adhesive composition according to any one of (1) to (3), wherein the acrylic polymer (A) has a weight average molecular weight (Mw) of 900,000 or less.

(5) The adhesive composition according to any one of (1) to (4), wherein the acrylic polymer (A) has a molecular weight distribution (Mw / Mn) of 3 or less.

(6) A single layer adhesive film comprising the adhesive composition according to any one of (1) to (5) above.

(7) An adhesive sheet in which an adhesive layer made of the adhesive composition according to any one of (1) to (5) is formed on a support.

(8) A semiconductor wafer is affixed to the adhesive layer of the adhesive sheet described in (7) above, and the semiconductor wafer is diced to form a semiconductor chip, and the adhesive layer remains fixed on the semiconductor chip and is peeled off from the support. And a method of manufacturing a semiconductor device, comprising: adhering the semiconductor chip onto a die pad portion or another semiconductor chip via the adhesive layer.

  When fixing the semiconductor chip, by using the adhesive sheet according to the present invention, it is possible to bond with sufficient adhesive strength and to obtain a semiconductor device exhibiting high package reliability even under harsh environments. .

  Hereinafter, the adhesive composition of the present invention, the adhesive sheet, and a method for producing a semiconductor device using the sheet will be described more specifically.

(Adhesive composition)
The adhesive composition according to the present invention is an acrylic polymer (A) (hereinafter also referred to as “component (A)”. The same applies to other components), an epoxy resin (B) (hereinafter referred to as “compound (B)”. ) "Or" component (B) "), the thermosetting agent (C) is included as an essential component, and other components may be included as necessary in order to improve various physical properties. Hereinafter, each of these components will be described in detail.

(A) Acrylic polymer The acrylic polymer (A) has a weight average molecular weight (Mw) of 350,000 or more, preferably less than 2,000,000, more preferably 400,000 to 1,800,000, and even more preferably 600,000. ˜1.5 million, particularly preferably 600,000 to 900,000. If the weight average molecular weight of the acrylic polymer is too low, package reliability may be impaired due to the fluidity of the low molecular weight component of the adhesive layer. On the other hand, if the weight average molecular weight of the acrylic polymer is too high, the adhesive layer may not be able to follow the irregularities on the substrate or chip surface, which causes generation of voids. By setting the weight average molecular weight of the acrylic polymer within the above range, the acrylic polymer has appropriate flexibility, the adhesiveness of the adhesive layer to the adherend surface having high surface smoothness is improved, and the chip and The substrate or the chip and the chip can be firmly bonded. In addition, it is possible to prevent a decrease in package reliability due to low molecular weight components. Furthermore, the acrylic polymer (A) of the present invention can sufficiently reduce the content of the low molecular weight component without reducing the weight average molecular weight by reducing the molecular weight distribution as described later. .

  The molecular weight distribution (Mw / Mn) of the acrylic polymer (A) is preferably 3 or less, more preferably 2 or less, still more preferably 1.7 or less, and particularly preferably 1.5 or less. . Acrylic polymers with a molecular weight distribution of 3 or less have a narrow molecular weight distribution even if the weight average molecular weight is high, so the content of low molecular weight components with high fluidity is low, and this low molecular weight component reduces the package reliability. There is a tendency that can be avoided. The lower limit of the molecular weight distribution is about 1.2 from the viewpoint of compatibility of each component.

  The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) values of the acrylic polymer (A) are gel permeation chromatography (GPC) method (polystyrene standard). Therefore, it is a value when measured under the measurement conditions in the examples described later. Moreover, when using the crosslinking agent (D) mentioned later, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the acrylic polymer (A) are the same as those of the crosslinking agent (D). It is the value before the reaction.

  The glass transition temperature (Tg) of the acrylic polymer is preferably in the range of −10 ° C. to 50 ° C., more preferably 0 ° C. to 40 ° C., and particularly preferably 0 ° C. to 30 ° C. If the glass transition temperature is too low, the peeling force between the adhesive layer and the support may increase and chip pickup failure may occur. If the glass transition temperature is too high, the adhesive force of the adhesive layer for fixing the wafer is insufficient. There is a risk.

  The monomer constituting the acrylic polymer (A) includes at least a (meth) acrylic acid ester monomer or a derivative thereof. (Meth) acrylic acid ester monomers or derivatives thereof include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Examples thereof include propyl acrylate, butyl (meth) acrylate and the like, and (meth) acrylic acid esters having a cyclic skeleton, such as (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, di And cyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc., and acrylic acid ester having a hydroxyl group, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate and the like, (meth) acrylic acid ester having a glycidyl group, such as glycidyl (meth) acrylate, and (meth) acrylic acid ester having an amino group, such as monoethylamino ( And (meth) acrylate and diethylamino (meth) acrylate. In addition, the acrylic polymer (A) has a hydroxyl group other than a (meth) acrylic acid ester such as a monomer having a carboxyl group such as (meth) acrylic acid or itaconic acid, vinyl alcohol, or N-methylol (meth) acrylamide. Monomers having (meth) acrylamide, vinyl acetate, acrylonitrile, styrene, and the like may be copolymerized.

  When the adhesive composition contains a crosslinking agent (D) described later, the acrylic polymer preferably has a functional group that reacts with the crosslinking agent (D) such as a hydroxyl group, an amino group, or a carboxyl group. Functionality that reacts with the crosslinking agent (D) on the acrylic polymer by selecting the above-mentioned acrylic acid ester having a hydroxyl group, monoethylamino (meth) acrylate, (meth) acrylic acid, etc. as the monomer constituting the coalescence (A) Groups can be introduced. In particular, the acrylic polymer (A) having a hydroxyl group is easy to introduce a hydroxyl group into the acrylic polymer (A), has good compatibility with the epoxy resin (B), and uses a crosslinking agent. Therefore, it is preferable because a cross-linked structure can be easily introduced. A plurality of types of acrylic polymers may be used in combination.

  When a functional group that reacts with the crosslinking agent (D) is introduced into the acrylic polymer (A) by using a monomer having a functional group that reacts with the crosslinking agent (D) as a monomer constituting the acrylic polymer (A). The ratio of the mass of the monomer having a functional group that reacts with the crosslinking agent (D) to the total mass of the monomer constituting the acrylic polymer (A) is preferably about 1 to 20% by mass, and 3 to 15% by mass. It is more preferable.

  The acrylic polymer (A) as described above is obtained by a method of living radical polymerization using an organic tellurium compound with the acrylic monomer as a polymerization initiator (hereinafter sometimes referred to as “TERP polymerization method”). It is. By adopting the living radical polymerization method, it becomes easy to adjust the molecular weight distribution (Mw / Mn) of the acrylic polymer (A), and the reliability of the semiconductor device using the adhesive composition of the present invention is improved. be able to. Moreover, the controllability of the molecular weight is improved by adopting the TERP polymerization method. It is particularly suitable for obtaining a high molecular weight polymer.

［式中、Ｒ¹は、炭素数１〜８のアルキル基、アリール基、置換アリール基又は芳香族ヘテロ環基を示す。Ｒ²及びＲ³は、水素原子又は炭素数１〜８のアルキル基を示す。Ｒ⁴は、アリール基、置換アリール基、芳香族ヘテロ環基、アシル基、オキシカルボニル基又はシアノ基を示す。］ As the tellurium-containing compound as such a living radical polymerization initiator, the following compounds are preferably used.

[Wherein, R ¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group or an aromatic heterocyclic group. R ² and R ³ represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an oxycarbonyl group or a cyano group. ]

Specific examples of the group represented by R ¹ are as follows. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, sec-butyl group, tert-butyl group, cyclobutyl group, and n-pentyl. Examples thereof include linear, branched or cyclic alkyl groups having 1 to 8 carbon atoms such as a group, n-hexyl group, n-heptyl group and n-octyl group. A preferable alkyl group is a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group.

As the aryl group, a phenyl group, a naphthyl group, etc., as a substituted aryl group, a phenyl group having a substituent, a naphthyl group having a substituent, etc., as an aromatic heterocyclic group, a pyridyl group, furyl Group, thienyl group and the like. Examples of the substituent of the aryl group having the above substituent include a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a nitro group, a cyano group, and a carbonyl-containing group represented by —COR ⁵ (R ⁵ = carbon number). 1-8 alkyl groups, aryl groups, C1-C8 alkoxy groups, aryloxy groups), sulfonyl groups, trifluoromethyl groups, and the like. Preferred aryl groups are a phenyl group and a trifluoromethyl-substituted phenyl group. These substituents may be substituted one or two, and the para position or ortho position is preferable.

Each group represented by R ² and R ³ is specifically as follows. Examples of the alkyl group having 1 to 8 carbon atoms include the same alkyl groups as those described above for R ¹ .

Each group represented by R ⁴ is specifically as follows. Examples of the aryl group, substituted aryl group, and aromatic heterocyclic group include the same groups as those described above for R ¹ . Examples of the acyl group include a formyl group, an acetyl group, and a benzoyl group. As the oxycarbonyl group, a group represented by —COOR ⁶ (R ⁶ ═H, alkyl group having 1 to 8 carbon atoms, aryl group) is preferable, and examples thereof include a carboxyl group, a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, Examples thereof include an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, an n-pentoxycarbonyl group, and a phenoxycarbonyl group. Preferred oxycarbonyl groups are a methoxycarbonyl group and an ethoxycarbonyl group.

Each group represented by R ⁴ is preferably an aryl group, a substituted aryl group, or an oxycarbonyl group. A preferred aryl group is a phenyl group. Preferred examples of the substituted aryl group include a halogen atom substituted phenyl group and a trifluoromethyl substituted phenyl group. In addition, in the case of a halogen atom, these substituents are preferably substituted by 1-5. In the case of an alkoxy group or a trifluoromethyl group, one or two substituents may be substituted. In the case of one substitution, the para position or the ortho position is preferable, and in the case of two substitutions, the meta position is preferable. . Preferred oxycarbonyl groups are a methoxycarbonyl group and an ethoxycarbonyl group.

As the tellurium-containing compound represented by the general formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, R ² and R ³ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , R ⁴ is preferably an aryl group, a substituted aryl group or an oxycarbonyl group. Particularly preferably, R ¹ represents an alkyl group having 1 to 4 carbon atoms, R ² and R ³ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁴ represents a phenyl group or a substituted phenyl group. A methoxycarbonyl group and an ethoxycarbonyl group are preferable.

  The tellurium-containing compound represented by the general formula (1) is specifically as follows. Examples of tellurium-containing compounds include (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl-propyl) benzene, 1-chloro-4- (methylterranyl-methyl) benzene, 1-hydroxy-4- (Methylterranyl-methyl) benzene, 1-methoxy-4- (methylterranyl-methyl) benzene, 1-amino-4- (methylterranyl-methyl) benzene, 1-nitro-4- (methylterranyl-methyl) benzene, 1-cyano- 4- (methylterranyl-methyl) benzene, 1-methylcarbonyl-4- (methylterranyl-methyl) benzene, 1-phenylcarbonyl-4- (methylterranyl-methyl) benzene, 1-methoxycarbonyl-4- (methylterranyl-methyl) benzene 1-phenoxycarbonyl-4- (methylterranyl- Methyl) benzene, 1-sulfonyl-4- (methylterranyl-methyl) benzene, 1-trifluoromethyl-4- (methylterranyl-methyl) benzene, 1-chloro-4- (1-methylterranyl-ethyl) benzene, 1-hydroxy -4- (1-methylteranyl-ethyl) benzene, 1-methoxy-4- (1-methylterranyl-ethyl) benzene, 1-amino-4- (1-methylterranyl-ethyl) benzene, 1-nitro-4- (1 -Methyl terranyl-ethyl) benzene, 1-cyano-4- (1-methyl teranyl-ethyl) benzene, 1-methylcarbonyl-4- (1-methyl teranyl-ethyl) benzene, 1-phenylcarbonyl-4- (1-methyl terranyl- Ethyl) benzene, 1-methoxycarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-phenoxy Rubonyl-4- (1-methylterranyl-ethyl) benzene, 1-sulfonyl-4- (1-methylterranyl-ethyl) benzene, 1-trifluoromethyl-4- (1-methylterranyl-ethyl) benzene [1- (1- Methylteranyl-ethyl) -4-trifluoromethylbenzene], 1- (1-methylterranyl-ethyl) -3,5-bis-trifluoromethylbenzene, 1,2,3,4,5-pentafluoro-6- ( 1-methylterranyl-ethyl) benzene, 1-chloro-4- (2-methylterranyl-propyl) benzene, 1-hydroxy-4- (2-methylterranyl-propyl) benzene, 1-methoxy-4- (2-methylterranyl-propyl) ) Benzene, 1-amino-4- (2-methylterranyl-propyl) benzene, 1-nitro-4- (2-methylterranyl-propyl) benzene 1-cyano-4- (2-methylterranyl-propyl) benzene, 1-methylcarbonyl-4- (2-methylterranyl-propyl) benzene, 1-phenylcarbonyl-4- (2-methylterranyl-propyl) benzene, 1-methoxy Carbonyl-4- (2-methylterranyl-propyl) benzene, 1-phenoxycarbonyl-4- (2-methylterranyl-propyl) benzene, 1-sulfonyl-4- (2-methylterranyl-propyl) benzene, 1-trifluoromethyl- 4- (2-methylterranyl-propyl) benzene, 2- (methylterranyl-methyl) pyridine, 2- (1-methylterranyl-ethyl) pyridine, 2- (2-methylterranyl-propyl) pyridine, 2-methyl-2-methylterranyl- Propanal, 3-methyl-3-methylteranyl-2-butanone, 2-methyl terranyl-methyl ethanoate, 2-methyl teranyl-methyl propionate, 2-methyl teranyl-2-methyl propionate, 2-methyl teranyl-ethyl ethanoate, 2-methyl terranyl-ethyl propionate, 2-methyl teranyl-2-methyl Ethyl propionate [ethyl-2-methyl-2-methylterranyl-propionate], 2- (n-butylterranyl) -2-methylpropionate [ethyl-2-methyl-2-n-butylterranyl-propionate], 2-methyl Terranylacetonitrile, 2-methylterranylpropionitrile, 2-methyl-2-methylterranylpropionitrile, (phenylterranyl-methyl) benzene, (1-phenylterranyl-ethyl) benzene, (2-phenyl) Terranyl-propyl) benzene etc. Can.

  Further, in the above, all compounds in which methyl teranyl, 1-methyl terranyl and 2-methyl terranyl are changed to ethyl teranyl, 1-ethyl teranyl, 2-ethyl terranyl, butyl terranyl, 1-butyl terranyl and 2-butyl terranyl, respectively, are included. Preferably, (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl-propyl) benzene, 1-chloro-4- (1-methylterranyl-ethyl) benzene, 1-trifluoromethyl-4 -(1-methylteranyl-ethyl) benzene [1- (1-methylterranyl-ethyl) -4-trifluoromethylbenzene], methyl 2-methylterranyl-2-methylpropionate, ethyl 2-methylterranyl-2-methylpropionate [ Ethyl-2-methyl-2-methylterranyl-propionate], 2- (n-butylterranyl) -2-methylpropionate [ethyl-2-methyl-2-n-butylterranyl-propionate], 1- (1-methylterranyl- Ethyl) -3,5-bis-trifluoromethylbenzene, 1,2,3,4,5-pe Tafluoro-6- (1-methylterranyl-ethyl) benzene, 2-methylterranylpropionitrile, 2-methyl-2-methylterranylpropionitrile, (ethylterranyl-methyl) benzene, (1-ethylterranyl-ethyl) benzene , (2-ethylteranyl-propyl) benzene, methyl 2-ethylteranyl-2-methylpropionate, ethyl 2-ethylteranyl-2-methylpropionate, 2-ethylterranylpropionitrile, 2-methyl-2-ethylterranyl Propionitrile, (n-butylteranyl-methyl) benzene, (1-n-butylteranyl-ethyl) benzene, (2-n-butylteranyl-propyl) benzene, 2-n-butylteranyl-2-methylpropionate methyl, 2- n-butyl terranyl-2-methylpropionate ethyl, 2- n-Butyl teranyl propionitrile and 2-methyl-2-n-butyl terranyl propionitrile are preferable.

  One of these tellurium-containing compounds represented by the general formula (1) may be used alone, or two or more thereof may be used in combination. When, for example, ethyl-2-methyl-2-methylterranyl-propionate is employed as the tellurium-containing compound represented by the general formula (1), a synthesis method thereof is disclosed in Japanese Patent Application Laid-Open No. 2011-74380. Can be obtained at

  In the polymerization step, an azo polymerization initiator may be added as a polymerization accelerator in addition to the tellurium-containing compound. The azo polymerization initiator is not particularly limited as long as it is an initiator used for ordinary radical polymerization. However, for example, 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis ( 2-methylbutyronitrile) (AMBN), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis (1-cyclohexanecarbonitrile) (ACHN), dimethyl-2 2,2′-azobisisobutyrate (MAIB), 4,4′-azobis (4-cyanovaleric acid) (ACVA), 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2 '-Azobis (2-methylbutyramide), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylamidinopropane) dihydrochloride, 2, 2'-azobis [2- (2-imi Zolin-2-yl) propane], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (2,4,4-trimethylpentane), 2 -Cyano-2-propylazoformamide, 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (N-cyclohexyl-2-methylpropionamide) and the like. When the azo polymerization initiator is used, it is preferably 0.01 to 100 mol, more preferably 0.1 to 100 mol, still more preferably 0 with respect to 1 mol of the tellurium-containing compound of the formula (1) used as the polymerization initiator. It is desirable to be used at a ratio of 0.1 to 5 mol.

  A method for forming the acrylic polymer (A) by living radical polymerization is, for example, as follows. In a container substituted with an inert gas, the mixture of monomers described above, the living radical polymerization initiator represented by the general formula (1) and, if desired, an azo polymerization initiator are mixed. At this time, examples of the inert gas include nitrogen, argon, helium, and the like. Argon and nitrogen are preferable. Nitrogen is particularly preferable. What is necessary is just to adjust suitably the usage-amount of a living radical polymerization initiator shown by a monomer and General formula (1) with the molecular weight or molecular weight distribution of the target acrylic polymer (A). The preferred amount used is a value (unit of amount used) divided by the weight average molecular weight (Mw) of the acrylic polymer (A) for the purpose of summing the values obtained by multiplying the molecular weight of each monomer by the charge ratio. Is the number of moles). In some cases, the amount is about 0.3 to 3 times the value.

  The polymerization is usually performed without a solvent, but an organic solvent generally used in radical polymerization may be used. Examples of the solvent that can be used include benzene, toluene, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, chloroform, carbon tetrachloride, tetrahydrofuran (THF), ethyl acetate, trifluoromethylbenzene, and the like. Can be mentioned. Moreover, an aqueous solvent can also be used, for example, water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, etc. are mentioned. The amount of the solvent used may be appropriately adjusted. For example, the solvent is 0.01 to 100 ml, preferably 0.05 to 10 ml, particularly preferably 0.05 to 0.5 ml per 1 g of the monomer. Is good.

Next, the mixture is stirred. The reaction temperature and reaction time may be appropriately adjusted depending on the molecular weight or molecular weight distribution of the acrylic polymer (A) to be obtained, but are usually stirred at 60 to 150 ° C. for 5 to 100 hours. Preferably, it is good to stir at 80-120 degreeC for 10 to 30 hours. The polymerization is usually carried out at normal pressure, but may be pressurized or reduced in pressure. After completion of the reaction, the intended acrylic polymer (A) is purified as necessary by removing the solvent and residual monomers under reduced pressure, precipitation filtration, reprecipitation, column separation, or the like by a conventional method. The reaction treatment can be performed by any treatment method as long as there is no problem with the object.
For example, in the acrylic polymer (A), the following fractionation method can be adopted in order to make the proportion of the low molecular weight component having a weight average molecular weight Mw of 50,000 or less contained in the acrylic polymer (A) 0.1 mass% or less. First, a lower alcohol such as methanol, ethanol, n-propanol, or isopropanol, or an aliphatic hydrocarbon having 5 to 10 carbon atoms such as pentane, hexane, or heptane, preferably 100 parts by mass of methanol or hexane, an acrylic polymer ( A) is added at a ratio of about 1 to 30 parts by mass as a solid content, and stirred at room temperature to form a precipitate. Next, the precipitate is subjected to solid-liquid separation by a method such as decantation, and then used after washing with the lower alcohol or an aliphatic hydrocarbon having 5 to 10 carbon atoms. By this fractionation method, the ratio of the low molecular weight component having a molecular weight Mw of 50,000 or less in the acrylic polymer (A) can be made 0.1 mass% or less.

  In this living radical polymerization method, an acrylic polymer (A) of a random copolymer can be obtained by using a mixture of monomers constituting the acrylic polymer (A). Regardless of the type of monomer, the random copolymer can provide a copolymer having a ratio (molar ratio) of monomers to be reacted. By using a tellurium-containing compound as a polymerization initiator, molecular weight control and molecular weight distribution control can be performed under very mild conditions. The molecular weight of the acrylic polymer (A) can be adjusted by the reaction time and the amount of the tellurium-containing compound. Specifically, in order to increase the molecular weight, the blending ratio of the tellurium-containing compound to the monomer may be reduced and the polymerization time may be increased. However, it takes a long time to obtain an acrylic polymer (A) having a large molecular weight. Thus, reduction of the polymerization time can be achieved by increasing the polymerization temperature or adding the azo polymerization initiator. However, if the polymerization temperature is too high, or if the amount of the azo polymerization initiator added is too large, the molecular weight distribution of the acrylic polymer (A) will be increased, so adjustment with it is necessary.

  The blending ratio of the acrylic polymer (A) in the total mass of the adhesive composition is preferably 35 to 90% by mass, more preferably 40 to 85% by mass, and 45 to 80% by mass. More preferably. In the method for manufacturing a semiconductor device in which the amount of the acrylic polymer (A) is limited as described above, the elasticity of the adhesive composition before curing is increased, and wire bonding is performed without curing the adhesive layer. There is a tendency that deformation of the adhesive layer is less likely to occur due to an impact at the time of bonding, and occurrence of defects is suppressed. Further, when the proportion of the acrylic polymer (A) in the adhesive composition is large, the weight average molecular weight (Mw) is 350,000 or more and the molecular weight distribution (Mw / Mn) is 3 or less. The effect of improving the package reliability of the present invention by using a certain acrylic polymer (A) becomes more remarkable.

(B) Epoxy-type thermosetting resin As an epoxy-type thermosetting resin (B), a conventionally well-known epoxy resin can be used. Specific examples of the epoxy thermosetting resin (B) include polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, orthocresol novolac epoxy resins, dicyclopentadiene type epoxy resins. And biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin and the like, and epoxy compounds having two or more functional groups in the molecule. These can be used individually by 1 type or in combination of 2 or more types.

  The adhesive composition preferably contains 1 to 100 parts by mass, more preferably 3 to 70 parts by mass of the epoxy thermosetting resin (B) with respect to 100 parts by mass of the acrylic polymer (A). Particularly preferably, 5 to 50 parts by mass are contained. The content of the epoxy thermosetting resin (B) is in such a range, so that sufficient adhesiveness is maintained, the elasticity of the adhesive layer is maintained, and even in the state before curing, the wire There is a tendency that deformation of the adhesive layer is less likely to occur due to an impact at the time of bonding in the bonding process, and occurrence of defects is suppressed.

(C) Thermosetting agent The thermosetting agent (C) functions as a curing agent for the epoxy thermosetting resin (B). Preferred examples of the thermosetting agent (C) include compounds having two or more functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Of these, phenolic hydroxyl groups, amino groups, acid anhydrides and the like are preferable, and phenolic hydroxyl groups and amino groups are more preferable. More preferably, a phenolic hydroxyl group and an amino group are mentioned.

  Specific examples of the phenolic curing agent include polyfunctional phenolic resin, biphenol, novolac type phenolic resin, dicyclopentadiene type phenolic resin, zylock type phenolic resin, and aralkylphenolic resin. A specific example of the amine curing agent is DICY (dicyandiamide). These can be used individually by 1 type or in mixture of 2 or more types.

  The content of the thermosetting agent (C) in the adhesive composition is preferably 0.1 to 500 parts by mass, and 1 to 200 parts by mass with respect to 100 parts by mass of the epoxy thermosetting resin (B). It is more preferable that If the content of the thermosetting agent (C) is small, the adhesiveness may not be obtained due to insufficient curing, and if it is excessive, the moisture absorption rate of the adhesive layer increases and the package reliability may be lowered.

(D) Crosslinking agent It is preferable to add a crosslinking agent (D) to the adhesive composition. Examples of the crosslinking agent (D) include organic polyvalent isocyanate compounds and organic polyvalent imine compounds. By introducing the crosslinked structure, the reliability of the semiconductor device using the adhesive composition of the present invention is improved. Living radical polymerization has a feature that the reaction at the active site is very gradual compared to free radical polymerization. That is, in free radical polymerization, since the reaction at the active site is very fast, it is considered that polymerization is performed from a monomer having high reactivity, and then a monomer having low reactivity is polymerized. On the other hand, in the living radical polymerization, since the reaction at the active site is slow, it is considered that the polymerization proceeds evenly without being affected by the reactivity of the monomer, resulting in an equivalent composition. As a result of the characteristics of the living radical polymerization, when a monomer having a functional group that reacts with the crosslinking agent (D) is used, the resulting acrylic polymer (A) reacts with the crosslinking agent (D). The monomer having the functional group to be absorbed is not taken into the polymer, and the probability that the molecule of the acrylic polymer (A) substantially having no functional group that reacts with the crosslinking agent (D) is generated is reduced. As a result, even if a low molecular weight acrylic polymer (A) molecule is present, it is highly likely to be incorporated into the three-dimensional network structure by reaction with the crosslinking agent, and the low molecular weight remaining without being incorporated into the three-dimensional network structure. It is considered that the possibility that the polymer of this will impair the package reliability is also reduced.

  Examples of the organic polyvalent isocyanate compound include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds. And a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyol compound.

  Examples of organic polyvalent isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane. -2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate, and their polyols Adduct body is mentioned.

  In the case of using an isocyanate-based crosslinking agent, the acrylic polymer (A) preferably has a hydroxyl group as a functional group that reacts with the crosslinking agent. When the crosslinking agent has an isocyanate group and the acrylic polymer (A) has a hydroxyl group, a bond between the crosslinking agent and the acrylic polymer (A) is easily formed by the reaction of the isocyanate group and the hydroxyl group, and the adhesive is crosslinked. The structure can be introduced simply.

  Examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri -Β-aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine can be exemplified.

  When an organic polyvalent imine compound is used as a crosslinking agent, the acrylic polymer (A) preferably has a carboxyl group as a functional group that reacts with the crosslinking agent. Bonding occurs between them, and a crosslinked structure is introduced into the adhesive.

  When using a crosslinking agent (D), a crosslinking agent (D) is 0.01-20 mass parts normally with respect to 100 mass parts of acrylic polymers (A), Preferably it is 0.1-10 mass parts, More preferably, it is 0. Used at a ratio of 5 to 5 parts by mass.

Other Components The adhesive composition can contain the following components in addition to the above components.

(E) Curing accelerator The curing accelerator (E) is used to adjust the curing rate of the adhesive composition. The curing accelerator (E) is preferably used particularly when the epoxy thermosetting resin (B) and the thermosetting agent (C) are used in combination.

  Preferred curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, 2-phenyl- Imidazoles such as 4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; Organic phosphines such as tributylphosphine, diphenylphosphine, triphenylphosphine; And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. These can be used individually by 1 type or in mixture of 2 or more types.

  When using a hardening accelerator (E), a hardening accelerator (E) becomes like this. Preferably it is 0.01-10 with respect to a total of 100 mass parts of an epoxy-type thermosetting resin (B) and a thermosetting agent (C). It is contained in an amount of part by mass, more preferably 0.1 to 1 part by mass. By containing the curing accelerator (E) in an amount within the above range, it has excellent adhesive properties even when exposed to high temperatures and high humidity, and high package reliability even when exposed to severe reflow conditions. Sex can be achieved. If the content of the curing accelerator (E) is small, sufficient adhesive properties cannot be obtained due to insufficient curing, and if it is excessive, the curing accelerator having a high polarity will pass through the adhesive layer under high temperature and high humidity. There is concern that the reliability of the package may be reduced by moving to and segregating.

(F) Energy ray polymerizable compound The energy ray polymerizable compound may be mix | blended with the adhesive composition. The energy ray polymerizable compound (F) contains an energy ray polymerizable group and is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams. Specific examples of such energy beam polymerizable compounds (F) include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or 1,4. Examples include acrylate compounds such as butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. Such a compound has at least one polymerizable double bond in the molecule, and usually has a weight average molecular weight of about 100 to 30,000, preferably about 300 to 10,000. When the energy beam polymerizable compound (F) is used, the blending amount is not particularly limited, but it is preferably used at a ratio of about 1 to 50% by mass in 100% by mass of the total solid content of the adhesive composition.

(G) Photopolymerization initiator When the adhesive composition contains the above-mentioned energy beam polymerizable compound (F), in use, the energy ray polymerizable compound is irradiated by irradiating energy rays such as ultraviolet rays. Harden. At this time, by including the photopolymerization initiator (G) in the adhesive layer, the polymerization curing time and the light irradiation amount can be reduced.

  Specific examples of such photopolymerization initiator (G) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal. 2,4-diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy- 2-methyl-1- [4- (1-methylvinyl) phenyl] propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and β-alkyl Examples thereof include roll anthraquinone. A photoinitiator (G) can be used individually by 1 type or in combination of 2 or more types.

  When using a photoinitiator (G), it is preferable that the mixture ratio is 0.1-10 mass parts with respect to 100 mass parts of energy-beam polymeric compounds (F), and 1-5 mass parts is contained. It is more preferable. When the amount is less than 0.1 parts by mass, satisfactory pick-up property may not be obtained due to insufficient photopolymerization. When the amount exceeds 10 parts by mass, a residue that does not contribute to photopolymerization is generated, and the curability of the adhesive layer is increased. It may be insufficient.

(H) Coupling agent The coupling agent (H) is a compound having a group capable of binding to an organic compound and a group capable of reacting with an inorganic compound, and bonding the coupling agent to an adherend of the adhesive layer. May be used to improve the property and adhesion. Moreover, the water resistance can be improved by using a coupling agent (H), without impairing the heat resistance of the hardened | cured material obtained by hardening | curing an adhesive bond layer.

  The group capable of binding to the organic compound of the coupling agent (H) is preferably a group that reacts with a functional group of the acrylic polymer (A), the epoxy thermosetting resin (B), or the like. As the coupling agent (H), a silane coupling agent is desirable. Such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxypropyl). ) Trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N- Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltrimethoxy Silane, meth Examples include rutriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, 3-isocyanatopropyltriethoxysilane, isocyanatemethylmethyldibutoxysilane, and isocyanatemethyltriethoxysilane. These can be used individually by 1 type or in mixture of 2 or more types.

  When the coupling agent (H) is used, the coupling agent is usually 0 with respect to a total of 100 parts by mass of the acrylic polymer (A), the epoxy thermosetting resin (B), and the thermosetting agent (C). 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass, more preferably 0.3 to 5 parts by mass. If the content of the coupling agent (H) is less than 0.1 parts by mass, the above effect may not be obtained, and if it exceeds 20 parts by mass, it may cause outgassing.

(I) Inorganic filler By blending the inorganic filler (I) into the adhesive composition, it becomes possible to adjust the thermal expansion coefficient of the adhesive layer, and after curing on a semiconductor chip, metal or organic substrate Package reliability can be improved by optimizing the thermal expansion coefficient of the adhesive layer. Moreover, it becomes possible to reduce the moisture absorption rate after hardening of an adhesive bond layer.

  Preferable inorganic fillers include powders such as silica, talc, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, spherical beads of these, single crystal fibers, and glass fibers. Among these, silica filler is preferable. The said inorganic filler (I) can be used individually or in mixture of 2 or more types. When using inorganic filler (I), the content can be normally adjusted in the range of 0 to 80% by mass with respect to 100 parts by mass of the total solid content of the adhesive composition.

(J) General-purpose additive In addition to the above, various additives may be blended in the adhesive composition as necessary. Various additives include plasticizers, antistatic agents, antioxidants, pigments, dyes, gettering agents and the like.

  The adhesive layer made of the adhesive composition comprising the above components has pressure-sensitive adhesiveness and heat-curing property, and has a function of temporarily holding various adherends in an uncured state. Finally, a cured product having high impact resistance can be obtained through heat curing, and it has excellent shear strength and can maintain sufficient adhesive properties even under severe high temperature and high humidity conditions.

  The adhesive layer may be a single-layer adhesive sheet formed by forming the above-mentioned adhesive composition, but preferably the adhesive layer made of the above-mentioned adhesive composition is formed on the support so as to be peelable. This is an adhesive sheet.

(Adhesive sheet)
Hereinafter, preferred embodiments and usage modes of the adhesive composition will be described by taking an adhesive sheet in which an adhesive layer is detachably formed on a support. When using an adhesive sheet in which the adhesive layer is formed so as to be peelable on the support, the adhesive layer is adhered to an adherend such as a wafer or chip, the support is peeled off, and the adhesive layer is attached. Transfer to the body. The shape of the adhesive sheet according to the present invention can be any shape such as a tape shape or a label shape.

  Examples of the support for the adhesive sheet include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide A film such as a film or a fluororesin film is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. Moreover, the film which colored these can be used. As for the transparency of radiation such as ultraviolet light and visible light, which the support has, an appropriate degree is selected according to its use.

  The adhesive sheet according to the present invention is affixed to various adherends, and after subjecting the adherend to necessary processing, the adhesive layer is left on the adherend to be peeled off from the support. That is, it is used for a process including a step of transferring an adhesive layer from a support to an adherend. For this reason, when the support is not subjected to pressure-sensitive adhesive treatment, the surface tension of the surface in contact with the adhesive layer of the support is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. It is. The lower limit is usually about 25 mN / m. Such a support having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the support and performing a release treatment.

  As the release agent used for the release treatment of the support, alkyd type, silicone type, fluorine type, unsaturated polyester type, polyolefin type, wax type, etc. are used, and in particular, alkyd type, silicone type, fluorine type release agent. Is preferable because it has heat resistance.

  In order to release the surface of the support using the release agent described above, the release agent can be applied directly with a gravure coater, Mayer bar coater, air knife coater, roll coater, etc. without solvent, or by solvent dilution or emulsion. Then, the laminate may be formed by room temperature or heating or electron beam curing, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like.

  The support may be a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on the resin film as described above, and the adhesive layer is detachably laminated on the pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet can be composed of a known pressure-sensitive adhesive having removability, and by selecting a pressure-sensitive adhesive such as an ultraviolet curable type, a heat-foaming type, a water swelling type, or a weakly viscous type. The adhesive layer can be easily peeled off.

  Further, the adhesive sheet may have a shape in which the support and the adhesive layer are previously punched in the same shape as the adherend (semiconductor wafer or the like) or in a concentric shape larger than the wafer shape. In particular, the laminate composed of the support and the adhesive layer is preferably in a form held on a long support.

  The thickness of the support is usually 10 to 500 μm, preferably 15 to 300 μm, particularly preferably about 20 to 250 μm. When the support is an adhesive sheet, the layer made of the adhesive usually occupies a thickness of about 1 to 50 μm in the thickness of the support. Moreover, the thickness of an adhesive bond layer is 2-500 micrometers normally, Preferably it is 6-300 micrometers, Most preferably, it is about 10-150 micrometers.

  In order to protect the adhesive layer, the adhesive of the adhesive sheet, the adhesive layer for fixing to the jig described below, etc., a release film is laminated on the upper surface of the adhesive layer before use. It may be left. As the release film, one in which a release agent such as a silicone resin is applied to a plastic material such as a polyethylene terephthalate film or a polypropylene film is used. In addition, an adhesive layer or an adhesive tape may be separately provided on the outer peripheral portion of the surface of the adhesive sheet in order to fix other jigs such as a ring frame.

  The method for producing the adhesive sheet is not particularly limited, and may be produced by applying and drying an adhesive composition on a support to form an adhesive layer. You may manufacture by providing on the peeling film for protecting a layer, and transferring this to the said support body.

  Next, a method of using the adhesive sheet according to the present invention will be described taking as an example the case where the adhesive sheet is applied to the manufacture of a semiconductor device.

(Method for manufacturing semiconductor device)
In the method for manufacturing a semiconductor device according to the present invention, a semiconductor wafer is attached to the adhesive layer of the adhesive sheet, the semiconductor wafer and the adhesive layer are diced into semiconductor chips, and the adhesive layer is formed on the back surface of the semiconductor chip. And a step of leaving the semiconductor chip on the die pad portion of the organic substrate or the lead frame, or placing the semiconductor chip on another semiconductor chip via an adhesive layer when the chip is stacked.

Hereinafter, a method for manufacturing a semiconductor device according to the present invention will be described in detail.
In the method for manufacturing a semiconductor device according to the present invention, first, a semiconductor wafer having a circuit formed on the front surface and a ground back surface is prepared.

  The semiconductor wafer may be a silicon wafer or a compound semiconductor wafer such as gallium / arsenic. Formation of a circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method. Next, the opposite surface (back surface) of the circuit surface of the semiconductor wafer is ground. The grinding method is not particularly limited, and grinding may be performed by a known means using a grinder or the like. At the time of back surface grinding, an adhesive sheet called a surface protection sheet is attached to the circuit surface in order to protect the circuit on the surface. In the back surface grinding, the circuit surface side (that is, the surface protection sheet side) of the wafer is fixed by a chuck table or the like, and the back surface side on which no circuit is formed is ground by a grinder. The thickness of the wafer after grinding is not particularly limited, but is usually about 20 to 500 μm.

  Next, the back side of the ring frame and the semiconductor wafer is placed on the adhesive layer of the adhesive sheet according to the present invention, lightly pressed, and heat is applied in some cases to fix the semiconductor wafer while softening the adhesive layer. Next, when the energy ray polymerizable compound (F) is blended in the adhesive layer, the energy ray polymerizable compound (F) is cured by irradiating the adhesive layer with energy rays from the support side. The cohesive force of the layer may be increased, and the adhesive force between the adhesive layer and the support may be reduced. Examples of the energy rays to be irradiated include ultraviolet rays (UV) and electron beams (EB), and preferably ultraviolet rays are used. Next, the semiconductor wafer and the adhesive layer are cut using a cutting means such as a dicing saw to obtain a semiconductor chip. The cutting depth at this time is a depth that takes into account the sum of the thickness of the semiconductor wafer and the adhesive layer and the wear of the dicing saw, and the adhesive layer is also cut to the same size as the chip. The energy beam irradiation may be performed at any stage after the semiconductor wafer is pasted and before the semiconductor chip is peeled off (pickup). For example, the irradiation may be performed after dicing or after the following expanding step. Good. Further, the energy beam irradiation may be performed in a plurality of times.

  Then, if necessary, when the adhesive sheet is expanded, the interval between the semiconductor chips is expanded, and the semiconductor chips can be picked up more easily. At this time, a deviation occurs between the adhesive layer and the support, the adhesive force between the adhesive layer and the support is reduced, and the pick-up property of the semiconductor chip is improved. When the semiconductor chip is picked up in this manner, the cut adhesive layer can be adhered to the back surface of the semiconductor chip and peeled off from the support.

  Next, the semiconductor chip is placed on the die pad of the lead frame which is the chip mounting portion or on the surface of another semiconductor chip (lower chip) through the adhesive layer. In order to improve the adhesiveness of the adhesive layer, the chip mounting portion is heated before mounting the semiconductor chip or heated immediately after mounting. The heating temperature is usually 80 to 200 ° C, preferably 100 to 180 ° C, and the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes. Moreover, the pressure of pressurization at the time of mounting is usually 1 kPa to 200 MPa.

  After the semiconductor chip is placed on the chip mounting portion, the adhesive layer is removed by heating before resin sealing without waiting for the main curing of the adhesive layer using heating in resin sealing as described later. It may be cured. The heating conditions at this time are in the above heating temperature range, and the heating time is usually 1 to 180 minutes, preferably 10 to 120 minutes.

  Alternatively, the adhesive layer may be cured by using heat in resin sealing that is normally performed in package manufacturing, without temporarily performing the heat treatment after placement. Through such a process, the adhesive layer is cured, and the semiconductor chip and the chip mounting portion can be firmly bonded. Since the adhesive layer is fluidized under die-bonding conditions, the adhesive layer is sufficiently embedded in the unevenness of the chip mounting portion, and generation of voids can be prevented and the reliability of the package is improved. In this case, the semiconductor chip mounted on the chip mounting portion via the adhesive layer is subjected to a wire bonding step in a state before the adhesive layer is cured. When such a process is adopted, the reaction of components contributing to the thermosetting of the adhesive layer partly proceeds due to heating in wire bonding, and there is a concern that the package reliability in the semiconductor device may be lowered. However, by using the adhesive composition of the present invention, the adhesiveness of the adhesive layer to the chip tends to be improved, and the package reliability tends to be maintained.

  The adhesive composition and adhesive sheet of the present invention can be used for bonding semiconductor compounds, glass, ceramics, metals, etc., in addition to the above-described methods of use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following examples and comparative examples, <GPC measurement> and <IR reflow resistance evaluation> were performed as follows.

<GPC measurement>
For the acrylic polymer used in each example, the weight average molecular weight Mw and the number average molecular weight Mn in terms of standard polystyrene are measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw / Mn) is determined from the measured values. Asked.
Measuring device: Tosoh's high-speed GPC device "HLC-8120GPC", high-speed columns "TSK gold column H _XL- H", "TSK Gel GMH _XL ", "TSK Gel G2000 H _XL " ) In this order and measured.
Column temperature: 40 ° C., liquid feed rate: 1.0 mL / min, detector: differential refractometer

<IR reflow resistance evaluation>
(Manufacture of semiconductor chips)
A tape mounter (manufactured by Lintec Corporation, Adwill) applies the adhesive sheets of Examples and Comparative Examples to the polished surface of a dry polished silicon wafer (150 mm diameter, 75 μm thick).
RAD2500) and fixed to a ring frame for wafer dicing. Next, the wafer was diced into a chip size of 8 mm × 8 mm using a dicing machine (Disco Corporation, DFD651). The amount of cut during dicing was such that the support was cut by 20 μm.

(Manufacture of semiconductor packages)
A circuit pattern is formed on a copper foil (18 μm thickness) of a copper foil-clad laminate (CCL-HL830 manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a substrate, and a solder resist (PSR-4000 AUS303 made by Taiyo Ink) is provided on the pattern. (LN001E-001 PCB (Au) AUS303, manufactured by Chino Giken Co., Ltd.). The chip on the adhesive sheet obtained above is picked up from the support together with the adhesive layer, and is pressure-bonded onto the substrate through the adhesive layer at 120 ° C., 250 gf, for 0.5 seconds, and further adhered onto the chip. Crimping was performed under the same conditions via an agent. Sealing was performed with a mold resin (KE-1100AS3 manufactured by Kyocera Chemical Co., Ltd.) so as to have a sealing thickness of 400 μm (sealing device MPC-06M TriAl Press manufactured by Apic Yamada Co., Ltd.), and the resin was cured at 175 ° C. for 5 hours. Next, the sealed substrate is affixed to a dicing tape (Adwill D-510T manufactured by Lintec Co., Ltd.), and dicing into 8 mm x 8 mm size using a dicing apparatus (Disco Co., Ltd., DFD651). A semiconductor package for evaluation was obtained.

(Evaluation of semiconductor package surface mountability)
The obtained semiconductor package was left to stand for 168 hours at 85 ° C. and 60% RH to absorb moisture, and then IR reflow with a maximum temperature of 260 ° C. for 1 minute (Reflow oven: WL-15-20DNX type, manufactured by Sagami Riko) 3 times, the presence / absence of floating / peeling of the joint portion and occurrence of package cracks were evaluated by a scanning ultrasonic flaw detector (Hye-Focus manufactured by Hitachi Construction Machinery Finetech Co., Ltd.) and cross-sectional observation. A case where peeling of 0.5 mm or more at the substrate / semiconductor chip junction was observed was judged as “bad”, and 27 packages were put into the test, and the number of good products in which peeling did not occur was counted.

<Synthesis example of acrylic polymer by TERP method>
As monomers, methyl acrylate (MA, manufactured by Tokyo Chemical Industry Co., Ltd.) and 2-hydroxyethyl acrylate (HEA, manufactured by Tokyo Chemical Industry Co., Ltd.) were used at a mass ratio of 95: 5, and polymerization was performed as follows. And an acrylic polymer (A-1) made of a random copolymer of MA / HEA was produced. First, 37.7 μL of ethyl-2-methyl-2-n-butylteranyl-propionate, 133 g of methyl acrylate (same as above), 7.0 g of 2-hydroxyethyl acrylate (same as above) and 2,2 ′ in a glove box substituted with argon. -8.1 mg of azobis (isobutylnitrile) (AIBN, manufactured by Otsuka Chemical Co., Ltd.) was reacted at 60 ° C for 20 hours.

  After completion of the reaction, the reactor was taken out of the glove box and dissolved in 500 ml of ethyl acetate, and then the polymer solution was passed through a column made of activated alumina [manufactured by Wako Pure Chemical Industries, Ltd.]. Ethyl acetate was added so that the viscosity of the polymer solution was 10,000 mPa · s (25 ° C.). The solid content of the obtained polymer was 17.3% by mass. In addition, the acrylic polymer (A) was prepared by living radical polymerization in the same manner as the acrylic polymer (A-1) except that the addition amount of ethyl-2-methyl-2-n-butylterranyl-propionate and AIBN and the polymerization time were adjusted. A-2), (A-3), and (A-5) were produced.

<Adhesive composition>
Each component which comprises an adhesive composition is shown below.
(A) Acrylic polymer:
(A-1) to (A-3) The types and mass ratios of acrylic polymer (A-4) monomers produced by the above synthesis examples and having the weight average molecular weight and molecular weight distribution shown in Table 2 are (A -1) Acrylic polymer having a weight average molecular weight and molecular weight distribution shown in Table 2 prepared by the free radical polymerization method (A-5) Manufactured by the above synthesis example by the TERP method, shown in Table 2. Table 2 produced by the free radical polymerization method in which the types and mass ratios of the acrylic polymer (A-6) and (A-7) monomers showing the weight average molecular weight and molecular weight distribution are the same as (A-1). Acrylic polymer (B) epoxy-based thermosetting compound having a weight average molecular weight and molecular weight distribution shown in FIG. 2; Bisphenol A type epoxy resin (Epicoat 828 manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 189 g / eq)
(C) Thermosetting agent: Novolac type phenolic resin (Showon High Polymer Co., Ltd. Shounol BRG-556, phenolic hydroxyl group equivalent 104 g / eq)
(D) Cross-linking agent; aromatic polyisocyanate (Nihon Polyurethane Industry Co., Ltd. Coronate L)
(E) Curing accelerator: Imidazole (Curesol 2PHZ manufactured by Shikoku Chemicals Co., Ltd.)
(H) Coupling agent; Silane coupling agent (MKC silicate MSEP2 manufactured by Mitsubishi Chemical Corporation)
(I-1) Inorganic filler; manufactured by Nissan Chemical Co., Ltd., silica sol MEK-ST
(I-2) Inorganic filler; MEK-AC-4101 manufactured by Nissan Chemical Co., Ltd.

(Examples and Comparative Examples)
(Adhesive layer)
Each said component was mix | blended in the quantity of Table 1, and the adhesive composition was obtained. Methyl ethyl ketone solution (solid concentration 61 mass%) of the obtained composition was dried on the release-treated surface of a release film (SP-PET 381031 manufactured by Lintec Co., Ltd.) that was release-treated with silicone so that the thickness became 10 μm. After coating and drying (drying conditions: 100 ° C. in an oven for 1 minute), bonding to a support (polyethylene film, thickness 100 μm, surface tension 33 mN / m) and transferring the adhesive layer onto the support An adhesive sheet was obtained. Table 2 shows the IR reflow resistance evaluation results of the obtained adhesive sheet.

Claims (8)

  An acrylic polymer (A) having a weight average molecular weight (Mw) of 350,000 or more obtained by polymerizing an acrylic monomer by a living radical polymerization method using an organic tellurium-containing compound as a polymerization initiator, an epoxy thermosetting resin ( An adhesive composition comprising B) and a thermosetting agent (C).   The adhesive composition according to claim 1, further comprising a crosslinking agent (D), wherein the acrylic polymer (A) has a functional group that reacts with the crosslinking agent.   The adhesive composition according to claim 2, wherein the crosslinking agent (D) contains an isocyanate group and the acrylic polymer (A) contains a hydroxyl group.   The adhesive composition according to any one of claims 1 to 3, wherein the acrylic polymer (A) has a weight average molecular weight (Mw) of 900,000 or less.   The adhesive composition according to any one of claims 1 to 4, wherein the acrylic polymer (A) has a molecular weight distribution (Mw / Mn) of 3 or less.   The single layer adhesive film which consists of an adhesive composition in any one of Claims 1-5.   An adhesive sheet in which an adhesive layer made of the adhesive composition according to claim 1 is formed on a support.   A semiconductor wafer is affixed to the adhesive layer of the adhesive sheet according to claim 7, the semiconductor wafer is diced to form a semiconductor chip, the adhesive layer remains fixed on the semiconductor chip and peels from the support, and the semiconductor A method for manufacturing a semiconductor device, comprising a step of bonding a chip onto a die pad portion or another semiconductor chip via the adhesive layer.